Preparation of barium salts of alkyl phenol sulphides



Patented Feb. 22, 1944 PREPARATION OF BARIUM SALTS F ALKYL. PHENOL SULPHIDES' Kennethn.AshlemNoroton, Conn, and Elmer W.

Cook; New York, Y., assignors to American Gyanam-id. Gompany New York, N. Y., a corporation ofQMalinc No nrawingi A plication: April 10,1942,

Serial No. 438,,43i

7'C lairns.

This invention relates to a new and improved method, of preparing barium salts or alkyl phenol sulphides; v

' In U. S. Patent.No;- 2-;270;183-, issued January 13; 1942, to wfocokand W. D: Thomas,=-dr.,

the said E. W; Cook being one of the inventors of the present invention, it is disclosed that the" 2;4-dia1kyl phenol sulphides and metal salts thereof, particularly-the barium salts, are highlye'fiective when addedto hydrocarbon lubricating oilsin the preventionpf sludge formation in the oil, varnish formation. on the pistons and other metallic parts of the' engine and in preventing corrosion of alloybea'rings. Other alkyl phenol sulphides, including-the polysulphides' as well asthe monoalkyl substituted phenol sulphides, particularly the barium salts thereof, are also effective when added to lubricating oils in the prevention of sludge formation and ascorrosion inhibitors.

The various barium alkyl' phen-olatesulphides ofvalue as lubricating oil additives. as sludge. dispersants and corrosion inhibitors whose preparation is contemplated by the present invention may be representedv by the following general formula R1 Ra: in which R and R2 are members of the groupconsisting; of hydrogen and alkyl radicals, Br and Rs are alkyl radicals and 1t is a small whole number; v v

So far as we are aware the barium salts of'the alkyl phenol sulphides have been prepared only by the neutralization of the alkyl, phenol sulphides. with barium oxide. or: barium. hydroxide.

Although. the preparation of. these bariumi salts" is conveniently-carried out: with, either bar um oxide or'barium.;hyjdroxide, the use of the{oxidev or hydroxide. presents. a number of disadvantages. Chemically the reaction involves the formation of one mole of water, which requires removal. from the;product-beiore it can bead'de'd to a lubricating oilas. a. corrosion inhibitor and sludge dispersant. and hydroxide are relatively expensive chemicals and, at the present time, not available in sufiicient quantities to prepare the barium salts of Economically, barium oxide alkyl phenol sulphides: in commercial quantities The high cost of barium oxide and bariunr hydroxide is based in. part uponthe difficultyof: preparing the compounds from available. rawmaterials. Commercial methods of preparation in-- volve igniting native sulphate or heavy spar with. coal, or charcoal, whereby anv impure barium sulphide is obtained. This is: converted intobarium. carbon-ate: by heating in; a. current of moist carbon dioxide. Super-heated. steam is thenp'a-ssed over the heated. carbonate, resulting. in the formation of? Ba(OH)-z and C02; BaO may be prepared by heating Witherite:v (BaCOx) in admixture with coal to 1100' to 1200 C.-.in a reducing: atmosphere; Unfortunately, however,. witherite is not available at: a reasonable cost, and it is: necessary to start with barytes. 38304)- and; prepare the barium hydroxide as outlined above.

Wehave now discovered that the. barium-z salts of alkyl' phenol sulphides may be prepared in: good yields and of satisfactory purity suitable; for use in the preparation of heavy duty, anti.- Sludge forming, anti-corrosion lubricating oils by the use of barium sulphide as' will hereinafter be described. The fact that barium sulphide can be employed for neutralization purposes inthe preparation of. these alkyl' phenol sulphides is very surprising since hydrogen sulphide is a stronger acid than phenol and one would ordina-rily predict that a phenol could not be neut'ral'izedwithbariumsulphide. This surprising effect is further accentuated by thefac't that the v alkyl substituents on the phenol radicals would ordinarilytend tofurther decrease the reactivity of the phenol.

The reaction is carried out by simply mixing finely ground BaS with a selected alkyl phenol sul hide dissolved in a suitable solvent such as. alcohol, mineral spirits or the like and heating the mixture under areflux; condenser with agitation in, the presence of a small. amount ofwater until the desired stage. ofereac'tion has been attained'. This may be determined by the evolu? tion of hydrogen sulphide (which is formed as. a result of the reaction. Whenhydrogen sulphide ceases to come ofi from the reaction mixture it may be assumed that the; reaction is-complete. Since. hydrogen sulphide is formed and isan. ob noxious gas, provision for its disposal should be made. The water remaining in the reaction product may then be removed by means of a water trap fitted to the reflux condenser and the product filtered to remove excess barium sulmineral barytes was crushed in ajaw crusher and stage-crushed on rolls to pass a 30-mesh screen. A sample of low ash anthracite coal was also crushed and passed through a 3D-mesh being evolved heating of the reaction mixture was continued. After about 5 hours heating the water in the reaction mixture was removed by means of a water trap fitted to the reflux condenser, 40 parts by weight of mineral spirits was then added and the productfiltered to remove unreacted barium sulphide and insoluble impurities contained in the black ash. The solvent was then removed by evaporation with stirring under a. vacuum. When about A; of the solvent was re moved a 10-W grade lubricating oil was blended with the reaction product to bring the final mixture to a content of 50% of the barium salt of 2,4-diamyl phenol monosulphide. The remainder screen. 100 parts of barytes and 19 parts of coal were then mixed and passed through a rotary kiln heated to a temperature of 1100 C. The crude product was found to contain 78% watersoluble BaS or acid-soluble material equivalent to about 90% Bail. The insoluble materials other than BaS are for the most part inert and are removed from the barium salt of the alkyl phenol sulphide by filtration at the completion of the neutralization reaction.

of the various alkyl phenol sulphides we prefer to employ the dialkyl phenol monosulph-ides in our process since the barium salts of these compounds have greater oil-solubility and better sludge-dispersing and anti-corrosion inhibiting characteristics than other alkyl phenol sulphides. The dialkyl phenol polysulphides, in which n in the'formula set forth hereinbefore is the small whole number 2 or 3, are easily oil-soluble but tend to be unstable at the sulphur linkage. The monoalkyl phenol sulphides have a decreased oil solubility since they contain but one alkyl group attached to each phenol radical. However, if the alkyl radical is of sufficient length, i. e. R1 and Rs are 'alkyl radicals of about 8 carbon atoms or more the compounds are readily oil-soluble and may be employed without difiiculty in the preparation of improved lubricating oils.

' Among the various alkyl phenol sulphides which may be reacted with barium monosulphide in accordance with our invention may be mentioned 2-,4-diamyl phenol monosulphide, 2,4-diamyl phenol disulphide, 2-methyl-4-tert. butyl phenol monosulphide, p-tert. butyl orthocresol monosulphide, 2-dodecyl-4-tert. amyl phenol monosulphide,- i-lauryl phenol monosulphide, 4-1auryl phenol disulphide, 4-n-octyl phenol monosulphide, 2,4-dioctyl phenol monosulphide, 2,4-dibutyl phenol monosulphide and others of similar character.

The preparation of a typical barium salt of an alkyl-phenol sulphide willnow be illustrated by the following example which is given, however, by way of illustration, since ourinvention in its broader aspects is to be limited only by the scope of .the .appended.claims.

...50'pa'r.ts by weight of 2.,4-diamyl phenol monosulphide was dissolved in approximately .40 parts by'weightof aromatic mineral spirits and was heated at refluxing temperatures under a reflux condenser withstirring with 10 parts by weight of; water and 21 parts by weight of finely ground blacl; ash (barium sulphide 80%) for 2 hours. At'this point it was found that 56% of the 2,4-v diamyl phenol monosulphide was neutralized to the corresponding barium salt. As HzS was still of thesolvent' was then removed by evaporation and the product was ready for use.

i What ,we claim is:

1. A method of preparing barium salts of alkyl phenolsulphides which comprises mixing and heating an alkyl phenol sulphide with barium sulphide in amounts sufficient to substantially neutralize'said alkyl phenol sulphide; a

2. A method of preparing barium saltsof di-Y alkyl phenol sulphideswhich comprises mixing adialkyl phenol sulphide with barium sulphide in amounts suificient to substantially neutralize said dialkyl phenol sulphide and heating the re.- action mixture until the evolution of hydrogen sulphide has substantially ceased.

3. A method of preparing barium salts of 2,4- diamyl phenol; monosulphide which comprises mixing 2,4-diamyl phenol monosulphide with barium sulphide in amounts sufiicient to substantially neutralize said ZA-diamyl phenol monosulphide and heating thereaction mixture until the evolution of hydrogensulphide has substantially ceased. v

4. A method of preparing barium salts 012A- dibutyl phenol .monosulphide which comprises mixing 2,4-dibuty1 phenol monosulphide with barium sulphidein amounts sufficient to substantially neutralize said 2,4-dibutyl phenol monosulphide and heatin the-reaction mixtureuntil the evolution of hydrogen sulphide has substantially ceased. v

5. A'methodof preparing barium salts of 4- alkyl phenol monosulphide which comprises mixing 4-alkyl phenol monosulphide with barium sulphide in amounts sufficient to substantially neutralize said 4-,alkyl phenol monosulphide and heating the reaction mixture until the evolution of hydrogen sulphide has substantially ceased.

6. A method of preparing barium salts of 4-00- tyl phenol monosulphide which comprises mixing 4- octyl phenol-monosulphide with barium. sul-.-. phide in amountssufiicient. to substantially neu tralize said. 4-octyl. phenol .monosulphide.anc 1 heating the reaction mixture until the evolution of hydrogen sulphide has substantially ceased.v

A method of preparingbarium salts of alkyl phenol sulphides which comprises mixing barium mono-sulphide, water andan .alkyl phenol sulphide dissolved .in a solvent and heatingthe re-..' action mixture at the refluxing temperature of the mixture until evolutionpf. vHzS has substantially ceased, separating insoluble material from the reaction mixture, and evaporating the solvent while concurrently adding thereto hydrocarbgn' lubricating oil. I

KENNETI-l D. ASHLEY. ELMER W. COOK. 

